1. Field
Embodiments of the present disclosure relate to an air conditioner capable of operating in an efficient cooling cycle while simultaneously guaranteeing superior cooling performance in a low-temperature operation region, and a method for controlling the same.
2. Description of the Related Art
An air conditioner is an apparatus that adjusts temperature, humidity, airflow, etc. of indoor air using movement of heat generated during evaporation and condensation of refrigerant that circulates in a cooling cycle including a compressor, a condenser, an expansion valve, and an evaporator.
Air conditioners may be classified into a split type air conditioner having an indoor unit and an outdoor unit separately installed, and an integrated type air conditioner having an indoor unit and an outdoor unit installed together in one cabinet. The split type air conditioner includes an indoor unit installed indoors and an outdoor unit connected to the indoor unit through a refrigerant pipe and installed outdoors.
The indoor unit of the air conditioner may include an indoor heat-exchanger (hereinafter referred to as an evaporator) configured to heat exchange between refrigerant and indoor air, and an indoor fan configured to flow and circulate indoor air. The outdoor unit of the air conditioner may include an outdoor heat-exchanger (hereinafter referred to as a condenser) configured to exchange refrigerant with outdoor air, a compressor configured to compress refrigerant and provide the compressed refrigerant to the condenser, and an outdoor fan (hereinafter referred to as a blowing fan) configured to flow and circulate outdoor air.
A typical air conditioner generally connects a single indoor unit to a single outdoor unit. However, in recent times, demand for a multi-system air conditioner which connects a plurality of indoor units to at least one outdoor unit to cool or warm indoor air of each space of a building (e.g., a school, a company, a hospital, etc.) having a plurality of independent spaces, is rapidly increasing.
Operation capacity of the outdoor unit of the multi-system air conditioner is changed according to change in capacity of the indoor unit, such that pressure of the condenser of the cooling cycle may excessively increase or decrease. The condenser pressure of the cooling cycle may be formed by heat-exchange between the condenser and outdoor air according to driving of the blowing fan. Generally, the higher the amount of heat exchange, the lower the condenser pressure. Since condenser pressure and evaporator pressure are directly associated with capacity and efficiency of the cooling cycle, the condenser pressure and the evaporator pressure should be formed in a compressor guarantee operation region.
The outdoor unit of the multi-system air conditioner may include an upper discharge-type outdoor unit through which heat-exchanged air is discharged upward, such that the air exchanges heat by natural convection of the air without driving the blowing fan at an outdoor low-temperature condition. Therefore, when the cooling operation is performed in an outdoor low-temperature condition, the multi-system air conditioner may have difficulty in guaranteeing the condenser pressure due to natural convection of the air and heat exchange between the condenser and the outdoor air by the blowing fan. If the condenser pressure is high, power consumption increases, resulting in reduction in efficiency of the cooling cycle. If the condenser pressure is low, the multi-system air conditioner deviates from the compressor operation region, resulting in reduction in compressor reliability.